In the Japanese laid-open application No. 6,112,558, published Jan. 20, 1986, the inventor has previously proposed a drive shaft for taking up sheets, which comprises a shaft, the outer periphery of which is formed with a plurality of inclined grooves circumferentially spaced apart and having the bottoms thereof inclined in the circumferential direction, rollers each accommodated in the inclined grooves so as to be capable of rolling in the longitudinal direction thereof, a plurality of sector-like members arranged side by side to surround the shaft inclusive of the rollers, and expansible retaining members retaining the sector-like members such that the sector-like members can be shifted radially outwardly. The sector-like members constitute the shaft, on which a sheet to be taken up is directly wound one or a plurality of turns, or on which a core for taking up a sheet thereon is fitted. The shaft is then rotated in a direction to cause the rollers to roll along the inclined grooves toward shallow portions thereof and thus project therefrom, thereby causing a radially outward shift of the sector-like members into tight engagement with the inner periphery of the wound sheet section or core for rotation in unison therewith so that the sheet is taken up.
This drive shaft has no problem so far as it is rotated in unison with the wound sheet section or core for taking up the sheet. However, since a plurality of sector-like members are arranged side by side to surround the inner shaft and the rollers, troublesome steps are required for its machining and assembly. More specifically, a set of sector-like members is prepared by preparing a ring-like material finished to a desired size using a lathe or the like and then radially precision-cutting the ring-like material into equal sector-like divisions with very narrow cutting gaps between the adjacent divisions. It requires a great deal of care on the part of the worker to accurately fix the ring-like member or sector-like divisions firmly to a vise or the like in a cutting posture and in a state such that the member or divisions will not be deformed. Further, it is necessary to machine the sector-like divisions to form recesses for accommodating the retaining members therein. Furthermore, the expansible retaining members have to be accommodated in the recesses formed in the machined sector-like divisions, (i.e., sector-like members), after setting these members on the outer periphery of the shaft. Where piano wires are used as the expansible retaining members to be accommodated in the recesses formed in the sector-like members on either inner or outer sides thereof, for example, some of the piano wires or some of the sector-like members are liable to detach during the work of retaining all sector-like members. Therefore, the assembling operation is very troublesome and time-consuming. Further, the retaining members are liable to detach during rotation of the drive shaft. Where the retaining members are bonded to the sector-like members, the bonding work has to be done very carefully lest the bonded retaining members should be detached. Furthermore, piano wires or steel springs used as the retaining members lead to machining difficulties although they can ensure excellent durability. Further, with the conventional continuously straight surface or curved inclined surface having no corrugation, it is difficult to temporarily lock the wound sheet or core which has already been set in position on the drive shaft.